1. Field of the Invention
The present invention relates to a chip carrier and, more particularly, to a chip carrier disposed in a package of a microwave semiconductor device for mounting a microwave semiconductor chip thereon. Furthermore, the present invention also relates to a high-power microwave semiconductor device using the chip carrier and a method of producing the microwave semiconductor device.
2. Description of the Related Art
Recently, high-power microwave semiconductor devices, which are used, for example, to amplify signals of a microwave band (1.about.30 GHz) for transfering to a communications satellite, have been studied and produced. Note, the microwave semiconductor device includes a semiconductor chip, an input matching circuit, an output matching circuit, and the like, which are provided in a package. The semiconductor chip comprises a plurality of FETs (Field Effect Transistors) to constitute an amplifier circuit for amplifying input microwave signals. The input matching circuit is used for impedance matching at an input side of the amplifier circuit, and the output matching circuit is used for impedance matching at an output side of the amplifier circuit.
In the high-power microwave semiconductor device according to the related art, the semiconductor chip is positioned between the input matching circuit and the output matching circuit, input side electrodes of the semiconductor chip are connected to electrodes of the input matching circuit by bonding wires, and output side electrodes of the semiconductor chip are connected to electrodes of the output matching circuit by bonding wires. Note, when producing (or assembling) the microwave semiconductor device, the semiconductor chip is directly disposed at a position between the input matching circuit and the output matching circuit in the package, and then, the semiconductor chip is fixed to the surface of the package by heating and melting gold-tin alloy and by carrying out a scrub process (which is a process of scrubbing the semiconductor chip on the surface of the package).
The high-power microwave semiconductor chip is formed thinly to effectively radiate the heat which is caused by itself, because the high-power microwave semiconductor chip consumes a large amount of power and a large amount of heat is produced thereby. Note, the semiconductor chip for a high-power microwave semiconductor device is, for example, made of a compound semiconductor material (GaAs, and the like), which is more delicate than a silicon (Si) semiconductor chip, and may be broken during the scrub process. Furthermore, when electrical characteristics of the semiconductor chip are ascertained to be inferior after fixing the semiconductor chip to the package, it is difficult to remove the semiconductor chip from the package, so that the semiconductor chip and the package which includes the matching circuits, and the like, must be all rejected.